That's a great point about moderation, plenty of forums outside of just banning would have mods post in the thread and say 'knock that shit off, try to be nicer' or whatever to discourage a toxic atmosphere.

There can be appropriate times for a range of civility like you said so having nuance is important, but I've rarely seen a forum outside of something like Stormfront afraid to ban Nazis or racists without question, unlike some big venues today that try to be 'tolerant' or 'free speech absolutists'.